Installation, Operationand Maintenance Manual

DC Motors

• Frames DC180ATZ, C180ATZ andDC210ATZ

2 DC Motors

General Description The products described in this publication are designed specifically for useon rectified power. The basic design includes Class F Insulation, 1.0 ServiceFactor, 40 degree C (104 degree F) ambient, continuous duty, withdrip-proof guarded and force-ventilated enclosure, with horsepower speedratings, overload and voltage in accordance with NEMA Standards. A widevariety of modifications, enclosures and accessories is available.

Table of ContentsGeneral Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Receiving and Handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Motor Application Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Disassembly & Reassembly Instructions. . . . . . . . . . . . . . . . . . . . . 21

Acceptance

Thoroughly inspect this equipment before accepting shipment from thetransportation company. If any of the goods called for in the bill of lading orexpress receipt are damaged or the quantity is short, do not accept themuntil the freight or express agent makes an appropriate notation on yourfreight bill or express receipt. If any concealed loss or damage is discoveredlater, notify your freight or express agent at once and request him to makean inspection. We are willing to assist you in collecting claims for loss ordamage in shipment; however, this willingness on our part does not removethe transportation company's responsibility in reimbursing you forcollection of claims or replacement of material. Claims for loss or damagein shipment must not be deducted from the invoice, nor should payment ofthe invoice be withheld awaiting adjustment of such claims, as the carrierguarantees safe delivery.

If considerable damage has been incurred and the situation is urgent,contact the nearest Allen-Bradley Sales Office for assistance. Please keep awritten record of all such communications.

!ATTENTION: Only qualified electrical personnel familiar withthe construction and operation of this equipment and the hazardsinvolved should install, adjust, operate, and/or service this motor.Read and understand this manual in its entirety beforeproceeding. Failure to observe this precaution could result inpersonal injury or loss of life.

DC Motors 3

Handling

In all cases, care should be taken to assure lifting in the direction intendedin the design of the lifting means. Lift using all lugs provided. Likewise,precautions should be taken to prevent hazardous overloads due todeceleration, acceleration or shock forces.

Angle of lift with rope or chain must be greater than 45 degrees fromhorizontal.

For unusual conditions, such as side-wall and ceiling mounting ofhorizontal motors or installation of vertical motors shipped in a horizontalposition, special precautions must be taken. It is recommended that anexperienced rigger be employed.

Storage

Motors must be stored in a clean, dry area protected from extremes oftemperature, moisture, shock and vibration. Storage temperatures of 10 to49 degrees C (50 to 120 degrees F) with a maximum relative humidity of60% must be observed. In addition, motors subjected to extended storagemust be handled and treated per the requirements specified in publication“Motors-5.0.” This publication is available from your Allen-Bradley SalesOffice or online at: http://www.controlmatched.com.

Installation DC motors have characteristics which can cause serious or fatal injuryunless they are selected, installed, maintained and operated by qualifiedpersonnel familiar with special requirements of DC machines.Allen-Bradley DC motors are designed and built in accordance with SafetyStandard for Construction and Guide for Selection, Installation and Use OfElectric Motors And Generators published by the National ElectricalManufacturers Association (NEMA), publication MG-2-1983 (ANSIC51.5). It is recommended that this publication be referred to whenever youselect or install any motor.

The application of motors and other electrical equipment in hazardouslocations is restricted by the National Electric Code. Users must observethese regulations and consult with local code inspection and enforcementagencies to insure compliance.

!ATTENTION: Eyebolt(s) or lifting lug(s) are intended forlifting the motor only with the standard accessories such astachometer, brakes, etc., mounted by Allen-Bradley. The liftingmeans on the motor must not be used to lift the unit plusadditional equipment. The lifting means on the motor cannot beused to lift assemblies or equipment mounted on a common base.Failure to observe this precaution could result in personal injury.

4 DC Motors

Location

Locate the machine where the ambient temperature is not over 40 degrees C(104 degrees F) and where clean air has free access to ventilating intake andoutlet openings. Except for machines with a suitable protective enclosure,the location should be clean and dry.

Important: Sufficient clearance must be provided on all inlet and outletopenings to provide for unrestricted flow of air. Separatelyventilated motors with exhaust to ambient (pipe-in only) musthave at least 152.4 mm (6 in.) of clearance between the openingand adjacent walls or floor.

Air Supply

Cooling air through a self-ventilated or forced-ventilated motor must beclean and have relative humidity between 30 and 100% with no free waterin the air. Use of damp, cool outside air with high humidity and free watermay cause the motor to flash over. Use of excessively dry air may causeexcessive brush and commutator wear. Cooling air temperature must notexceed the maximum ambient temperature indicated on the motornameplate (standard 40 degrees C/104 degrees F). Cooling air temperaturemust not be lower than 0 degrees C (to provide base speed and regulationwithin NEMA limits). Use of outside air below 0 degrees C may causeexcessive brush and commutator wear due to the low humidity. Cooling airabsolute humidity must be at least 2 grains per cu. ft.

Important: Motors located in damp, moist environment must have spaceheater or fields energized at 50% voltage to protect againstcondensation when motor is not operating.

Separately ventilated motors must have the following volume of air toadequately cool the motor unless the motor nameplate specifies a differentvalue.

Power Supply

Check the motor nameplate to be sure the voltage and type of power ratingis the same as that of the power source.

A code stamped on the nameplate identifies the type of power supply thatmust be used to supply armature power to the motor in order to obtain therated nameplate output. Since the code letter has been selected in alphabeticorder of increasing magnitude of ripple current, a motor may be operated ona power supply having a letter designation prior in the alphabet to the letterstamped on the nameplate, with no loss in nameplate rating.

FrameBase SpeedRPM

Air VolumeCFM

Static PressureInches of Water

DC180ATZ,C180ATZ andDC210ATZ

2500 152 2.01750 and lower 105 0.95

DC Motors 5

For example, a motor designed for a D type of power supply may be usedon a C power supply having the same voltage rating. The types of powersupplies are defined as follows.

1 When the armature power supply cannot be designated by a single letter code (A. K etc.) the power supply shallbe identified by the following code stamped on the motor nameplate: “M/N F-V-H-L.”

where M = Total pulses per cycleN = Total controlled pulses per cycleF = Free wheeling (if used)V = Nominal line-to-line a-c voltage to rectifierH = Line frequency-HzL = Value of series inductance (in millihenries) to be added externally to the motor armature circuit.

Examples:A. "6/3 F-380-50-12" defines a power supply having 6 total pulses per cycle, 3 controlled pulses per cycle

(S-3), with free wheeling, 380 volts. 50 Hz AC input to bridge, and a 12 millihenry choke to be addedexternally to the motor armature circuit.

B. "3/3 480" defines a power supply having three total pulses per cycle, three control pulses per cycle. 480volts line-to-line input to the rectifier. 60 Hz power supply and no external inductance required in thearmature circuit. Note that since the power source is 60 Hz and no series inductance is required. bothquantities may be omitted from the code. If one of the quantities is indicated, both must be included toavoid confusion.

Conduit BoxConduit boxes can be rotated in 90 degree increments for lead outlet at top,sides or bottom.

Conduit box locations can be changed from F1 to F2 or F2 to F1 by rotatingthe commutator end bracket 180 degrees and reconnecting the leads. Theconduit box location cannot be changed on DC180ATZ & DC210ATZframes.

Connections

Important: If motor has parallel leads, all lugs with the same marking: Forexample, A1, A1, must be connected together.

Figure 1 Basic DC Motor and Generator Connections

If machine has no series field, disregard S1 and S2 above. For machineswith special windings, refer to motor or generator and controller diagrams.

Description Code1

DC generator, battery or twelve pulse/cycle, 6 phase, full control ASix pulse cycle, 3 phase, full control 230 or 460 volt, 60 Hz input to rectifier CThree pulse/cycle, 3 phase, semi-bridge, half control 230 or 460 volt, 60 Hz input to rectifier DThree pulse/cycle, 3 phase, half-wave (single way) 460 volt, 60 Hz input to rectifier ETwo pulse/cycle, 1 phase full wave (bridge circuit with 2 controlled rectifiers and2-uncontrolled rectifiers with free wheeling rectifier) 230 volt, 60 Hz input

K

+A1Motor

Type CCW

Rotation Facing Commutator End

CW

A2

S1

–S2

+F1

–F2

A1

+A2

S1

–S2

+F1

–F2

A1Generator

+A2

S1

–S2

–F1

+F2

A1

+A2

–S1

S2

+F1

–F2

6 DC Motors

Thermostat (Thermal Protector)

Important: When motors are provided with thermal protection (typicallythermostats), it is important to properly connect and apply thedevices. This will ensure that the motor is properly protectedfrom being operated if thermal limits are reached and/orexceeded. The control system must be configured to reduce themotor load and/or shut down the motor control system to allowthe motor to cool to a level within acceptable operating ranges.If the motor is operated with the thermal protective devicestripped (indicating an over temperature condition), the motorinsulation could be damaged and complete failure of the motorinsulation is possible. In the event of motor failure due to anover temperature condition, Rockwell Automation requires thatmotor thermal protective devices (when supplied) beadequately monitored and incorporated into the motor controlsystem to maintain warranty. Failure on the part of theindividual installing this equipment to take these steps willresult in the factory warranty being voided.

Important: Motors may have one or more thermostats (leads marked P1,P2, etc.) designed to trip before the frame reaches themaximum allowable temperature for specific class and group.The normally closed contacts of the thermostat must beconnected in that motor control circuit so that power to themotor armature and field is removed immediately when thethermostat trips. An explosion-proof tachometer mounted onthe motor will also have an internal thermostat which must beconnected to stop the drive within 30 seconds upon tripping.Failure to connect the thermostat leads will void the motorwarranty. the rating of the thermostat contact is:

Important: Motors with an overspeed switch must have the overspeedswitch terminals properly connected in the control circuit toremove armature power when the switch reaches the set speed.

Grounding

The user is responsible for assuring that the grounding method is inaccordance with the National Electric Code and the applicable local codes.The ground connection should be a solid and permanent metallicconnection between the ground point, the motor terminal housing and themotor frame. On two pole units, DC180ATZ, C180ATZ & DC210ATZ, theground connection is a tapped hole in the end bracket adjacent to theconduit box.

Maximum Voltage 250V, 60 HzRated Current 6.3 ampsMaximum Breaking Current 20 amps

DC Motors 7

Mounting

Motors must be mounted on a rigid, solid base or foundation. Poor baseconstruction may cause resonances in the motor/base assembly which canresult in bearing failure and other motor damage. All hold down bolts mustbe the correct grade for the type of mounting and must be torqued to theirrecommended value.

Table A Recommended Torque

Belted Drive

Motor slide bases or rails, when used, must be securely anchored to thefoundation with the proper bolts.

Important: The motor shaft and load shaft must be parallel and the sheavesaligned. Refer to “Motor Application Data” on page 8.

Coupled Drives

Important: Flexible couplings must be used between the motor shaft andthe load shaft. Motor shaft and load shaft must be aligned tovalues recommended for the specific coupling before couplingis connected.

Important: Motors will operate successfully mounted on the floor, wall orceiling, and with the shaft at any angle from horizontal tovertical. Special mountings, duty or thrust demands may,however, require a different bearing system. Drive-end bracketand/or outer caps can be rotated either 90 or 180 degrees toconveniently locate grease fittings, or air outlet openings.Handhole covers can be interchanged as necessary.

Important: Vertical mount drip covers are required to provide protection tovertically mounted Drip-Proof motors. Stock motors and othermotors designed for horizontal mounting can be adapted forvertical mounting by ordering vertical mount drip covers.Self-ventilated frames cannot be mounted vertical shaft up andretain the drip-proof feature due to louvers on the drive endbracket.

Motor C-Face is intended for mounting auxiliary equipment such as pumps,gears, etc. When mounted horizontally, these motors should be supportedby the feet and not by the C-Face. Installations requiring a horizontallymounted motor without feet should use a D-Flange.

FrameHole Diametermm (in.)

Bolt Size andThread

SAE Grade I Dry Components-Not LubricatedN-m (lb.-ft.)

C180ATZ 11.2 (0.44) 3/8-16 1.81 (16)

!ATTENTION: Surface temperature of the motor enclosure mayreach temperatures which can cause discomfort or injury topersonnel coming into contact with hot surfaces. The user mustapply appropriate guards and/or shields to protect againstaccidental contact with motor surface. Failure to observe thisprecaution may result in personal injury.

8 DC Motors

Direction of Rotation

Unless otherwise ordered, brush rigging is assembled for NEMA standarddirection of rotation, counterclockwise for motors and clockwise forgenerators facing the commutator end. These motors will operate in eitherdirection of rotation, without changing the angle of the brush holders fornormal field weakened speed ranges. Extended field weakened speed rangemotors should have the direction of rotation specified.

Drive

DC180ATZ, C180ATZ & DC210ATZ frame motors are supplied with ashaft suitable for a belt or coupled drive.

Proper alignment is a key step for long life of bearings, shafts and belts, andminimum downtime. Misalignment can cause excessive vibration anddamaging forces on shaft and bearings. For direct coupled drives, flexiblecouplings facilitate alignment. For belt drives, the driving and driventension must be adjusted as required for proper operation. The belt sheavesshould be placed as close as possible to the motor bracket.

Shipping Blocks

Motors supplied with roller bearings at the drive end are shipped withwooden blocking to prevent axial movement of the shaft during shipment.Remove the blocking and bolts securing it and discard. Make sure motorshafts turn freely. If motor is to be reshipped, blocking of bearing isrequired.

Motor Application Data Maximum Safe Speed

!ATTENTION: To guard against personal injury and/or machinedamage caused by incorrect motor rotation, verify direction ofmotor rotation before coupling motor to load.

!ATTENTION: Ensure that all guards are properly installed, toguard against personal injury caused by contact with rotatingparts,

!ATTENTION: The machinery builder and/or user areresponsible for assuring that all drive train mechanisms, thedriven machine, and process material are capable of safeoperation at the maximum speed at which the machine willoperate. Failure to observe these precautions could result inpersonal injury.

DC Motors 9

The speeds given in Table B are the maximum mechanically safe operatingspeeds for frames with standard construction. These speeds must not beexceeded under any condition. Motor control must hold the maximumspeed under any load condition including no-load within the maximum safespeed. Drive systems whose design characteristics inherently prevent theDC motor from exceeding the motor maximum safe operating speed mustprevent the motor from exceeding the maximum safe speed if a singlecomponent failure should occur.

Table B Maximum Safe Speed

With special construction, maximum safe speed may differ from the abovevalues. In all cases, maximum safe speed is indicated on the motornameplate.

Important: Normal operating speeds must be limited to those listed inorder to meet nameplate rating and assure validity of warranty.

Application of Pulleys, Sheaves, Sprockets and Gears On Motor Shafts

To avoid excessive bearing loads and shaft stresses, belts should not betightened more than necessary to transmit the rated torque. Thepre-tensioning of the V-belt drive should be based on the total tighteningforce required to transmit the horsepower divided by the number of belts.This procedure avoids the excessive load caused by tightening individualbelts to a prescribed level recommended by belt manufacturers.

Mounting

In general, the closer pulleys, sheaves, sprockets or gears are mounted to thebearing on the motor shaft, the less will be the load on the bearing. This willgive greater assurance of trouble-free service.

The center point of the belt, or system of V-belts, must not be beyond theend of the motor shaft.

The inner edge of the sheave or pulley rim should not be closer to thebearing than the shoulder on the shaft but should be as close to this point aspossible.

The outer edge of a chain sprocket or gear must not extend beyond the endof the standard motor shaft.

Frame Diameter Maximum Safe SpeedDC180ATZ 4500 RPMC180ATZ 5000 RPMDC210ATZ 4500 RPM

10 DC Motors

Shaft Extension and Method Of Drive

V-belts should be within the limits of NEMA Standard MG1-14.67.a.Frames DC180ATZ, C180ATZ, DC210ATZ are supplied with the same sizeshaft for either coupled or belted drives.

Table C Multipliers for Drives other than V-belt

1 The above multiplier is intended for use with conventional single-ply flat, belts. When other than single-ply flat beltsare used, the use of a larger multiplier is recommended.

2 It is often necessary to install belts with a snug fit. However, tension should be no more than necessary to avoidbelt slap or tooth jumping.

Shaft Loads – Axial and Radial

DC motors are suitable for limited shaft load as shown in Tables D and E.Recommended maximum thrust loads depend on the mounting position,either horizontal or vertical. For load recommendations in excess of thoseshown, contact your local Sales Office.

Table D Axial Thrust Capacity1

1 Thrust capacity for vertical mounting includes a constant whose value is plus or minus depending on thedirection of the thrust load. The constant is plus for thrust loads acting upward against the force of gravity andminus for loads acting downward with gravity.

Drive MultiplierFlat Belt (See Note 1) 1.33Timing Belt (See Note 2) 0.9Chain Sprocket 0.7Spur Gear 0.75Helical Gear 0.85

!ATTENTION: The use of these radial load capacities requiresthe accurate calculation of the radial load for the application.Radial loads for gears, sprockets, and flywheel are usuallyaccurately determined but the radial loads due to V-belt drives aresubject to miscalculations because they do not include all of thepre-tension load (belt tightening). The calculations of the radialload for a V-belt drive must include the pre-tension fortransmitting the horsepower, pre-tension for centrifugal force onthe belts, pre-tension for high start torques, rapid acceleration ordeceleration, pre-tension for drives with short arc-of-contactbetween the V-belt and sheave, and low coefficient of frictionbetween belt and sheave caused by moisture, oil or dust. Failureto observe these precautions could result in damage to ordestruction of the equipment.

Frame UnitsHorizontal Mounting Vertical Mounting2500 RPM 1750 1150 850 2500 1750 1150 850 RPM

DC180ATZ &DC210ATZ

lbs. 176 207 251 286 190 ± 45 217 ± 45 265 ± 45 295 ± 45kg 80 94 114 130 86 ± 20 99 ± 20 120 ± 20 134 ± 20

C180ATZ lbs. 295 345 417 477 370 ± 45 357 ± 45 430 ± 45 492 ± 50kg 134 156 189 216 139 ± 20 162 ± 20 195 ± 20 223 ± 20

DC Motors 11

Table E Radial Load Capacity1

1 Data for motors with roller bearings at the drive end (back end). Motors with ball bearings at the drive end arefor coupled duty only.

Deriving Motor Constants

Various motor constants are required to set control functions for stabilizedoperation of motor and controls. The following information will make itpossible to derive approximate motor constants from the nameplate data.

Required Nameplate Data

• Frame• HP• RPM• Volts (Va)• Amps (Ia)

From Table F, the following factors are available, based on frame size.

• Ra´• La´• WK2

• τe´

This will provide approximate results with a ±25% margin of error.

The following data can be derived:La = La´ x (Va/rpm)2 Arm. Circ. Ind. (millihenries)Ra = Ra´ x (Va/rpm)2 Arm. Circ. Resistanceτe = τe´τe´ = La/Ra x 103 Elec.Time ConstantJ (SEC) = WK2 x (rpm)2/1.62 x (10)6 x hp where WK2 is in terms of lb-ft2

J (SEC) = WK2 x (rpm)2/0.0922 x (10)6 x kw where WK2 is in terms of kg-m2

R = Ia x Ra/(Va – IaRa)

Table F Resistance & Inductance Factors

FrameCapacity at End of Shaft in kg (lbs.)2500 RPM 1750 RPM 1150 RPM 850 RPM

DC210ATZ &DC180ATZ

140.6 (310) 156.5 (345) 179.2 (395) 200.0 (440)

C180ATZ 226.8 (500) 256.3 (565) 283.5 (625) 283.5 (625)

FrameWK2

Ra La τelb.-ft.2 kg.-m.2

C1811ATZ 0.683 0.029 56.6 616 0.011C1812ATZ 0.787 0.033 40.5 500 0.012

12 DC Motors

Operation Balance

Motors are dynamically balanced to commercial limits unless ordereddifferently. Balance is done with a full length 1/2 height shaft key. A fullshaft key is shipped with the motor. Sheave or coupling should be balancedwith a 1/2 height shaft key.

Table G Standard Dynamic Balance Limits

Series Wound Motors

Important: Series wound motors must be solidly connected to the drivenmachine and never operated without load to avoid possibledestructive high speeds.

Motor Start-up

Highest Rated Speed(RPM)

Maximum Amplitude(Inches)

3,000 - 4,000 0.00101,500 - 2,999 0.00151,000 - 1,499 0.0020Up to 999 0.0025

!ATTENTION: To guard against personal injury and/or machinedamage, observe the following precautions before initial start-up:

• Remove all unused shaft keys and loose rotating parts toprevent them from flying off. Replace covers and protectivedevices.

• Verify that all separately excited fields are excited at their ratedvoltage and that relative polarities of all fields are correct. See“Checking Relative Polarity of DC Motor Fields” on page 14.

• When the motor is supplied as part of drive system, refer to theDrive User Manual for operating instructions. Tachometerfeedback must be properly connected for closed loopoperation. Reverse polarities or broken connections can causedangerous overspeeds.

Maximum safe mechanical operating speeds are shown inTable B on page 9. Motor control circuitry must prevent motorspeeds from exceeding the stated values.

DC Motors 13

In addition to observing the above precaution, all precautions (Attentions)mentioned in this document should be observed. The following items mustbe checked before starting and during operation.• The armature should rotate freely and be clear of any obstructions.• The brushes should move easily in their holders and should make

proper contact on the commutator.• The interior of the motor should be clean and dry.• Connections must be tight.• The driven machine should be unloaded, if possible.

When starting, small sparks may appear on the commutator due to particlesof dirt. Other than this. there should be little, if any, sparking at the brushes.

Important: Machines designed for cooling by a separate source of forcedventilation must not be operated without the air supply. Be sureblower is running in proper direction.

While operating the motor, observe the performance. It should run smoothlywith little noise. The bearings should not overheat and should reach aleveling off temperature. Any undue noise, overheating, sparking or erraticperformance should be investigated and necessary corrective action takenimmediately to prevent serious damage. Before attempting any repairs,please contact your Allen-Bradley Sales Office.

All motors are lubricated before shipment and will operate for a long periodbefore regreasing is required. The period will vary depending onenvironmental and service conditions. Refer to “Maintenance” on page 15.

!ATTENTION: Surface temperature of the motor enclosure mayreach temperatures which can cause discomfort or injury topersonnel coming into contact with hot surfaces. The user mustapply appropriate guards and/or shields to protect againstaccidental contact. Failure to observe this precaution may resultin personal injury.

14 DC Motors

DC Motor Field Heating

Standard continuous duty DPG, TEFC and TENV stabilized shunt woundDC motors have continuous duty fields capable of continuous excitation atstandstill (armature circuit not energized) under normal industrialconditions.

Important: Motors designed for forced ventilation or with a dual-cooledheat exchanger as standard must have cooling air when fieldsare excited at rated voltage. Installations having the air supplyinterrupted when the motor is not operating must have fielddisconnected or field voltage reduced to 50% rated by means offield economizing resistor and relay.

Standard continuous duty self-ventilated motors are suitable for rated loadat rated speed operation at field voltages up to 110% of rated value.However, insulation life will be reduced if operated below 60% of basespeed for prolonged periods.

Checking Relative Polarity of DC Motor FieldsMotor speed is unstable if speed increases due to an increase in loadcurrent. As a result of instability, motor speed may hunt or overspeed. Theseare unsatisfactory, possibly dangerous, drive conditions.

One of the possible causes of unstable performance of shunt wound DCmotors is incorrect series field polarity relative to the shunt field due toimproper connection. Relative polarity of the shunt and series fields can bechecked as follows:

1. Connect a low scale (3 volt) DC voltmeter across the shunt fieldterminals (F1, F2) with F1 connected to the positive (+) terminal of themeter. At least one of the shunt field leads must be disconnected fromthe controller.

2. Use two flashlight batteries as a source of low voltage (3 volts). Hold orconnect the negative, to contact the S-2 series field terminal. Hold oneend of a wire conductor to the positive (+) center terminal so that theother end of the wire can be used to make and break contact with the S-Iseries field terminal.

3. Watch the deflection of the voltmeter needle when contact is made withS-I and when contact is broken.

!ATTENTION: To guard against motor damage caused byinadequate ventilation, assure that motors designed for forcedventilation as standard have cooling air when fields are excited atrated voltage. Installations having the air supply interrupted whenthe motor is not operating must have field disconnected or fieldvoltage reduced to 67%, rated by means of field economizingresistor and relay. The motor insulation life can be significantlyreduced if the above precaution is not followed.

DC Motors 15

4. When contact is made, the needle will first deflect in either the up scaleor down scale direction and then return to zero. Deflection will be in theopposite direction when contact is broken.

5. Relative polarities of the shunt and series fields are correct(ampere-turns are cumulative) if the voltmeter needle deflects up scalewhen contact is made and down scale when contact is broken.

6. Relative polarities of the shunt and series fields are incorrect(ampere-turns are differential) if the voltmeter needle deflects downscale when contact is made and up scale when contact is broken. Themotor connections must be changed so that relative polarity is correct.

Relative polarity can be incorrect because of an error in the connections tothe control or because the series fields leads are improperly marked. In anycase, the motor connections must be changed so that relative polarity iscorrect.

If only one series field terminal is available at the controller, use it and theavailable armature terminal for the test. For example, use S-2 and A-l, if S-1and A-2 arc connected together at the motor and not brought to thecontroller.

Maintenance

Inspections

Regular inspection at intervals dependent upon service conditions is the bestinsurance against costly maintenance and breakdown. Experience is the bestguide. Record inspection results and maintenance action required orperformed.

Cleanliness

Keep the interior parts of machines clean and dry. Remove dust, dirt,corrosion, grease, oil and moisture. If used, ventilating air filters must bekept clean or replaced to assure full volume of cooling air.

Lubrication - Frames DC180ATZ & DC210ATZ

DC180ATZ frame has oversize grease reservoirs to provide lifetimeoperation in normal industrial applications. Where severe duty conditionsrequire regreasing, the following procedures should be followed:

!ATTENTION: Internal parts of this motor may be at linepotential even when it is not rotating. Before performing anymaintenance which could result in contacting any internal part, besure to disconnect all power from the motor. Failure to observethis precaution could result in severe personal injury or death.

16 DC Motors

Drive End BearingBearing fits in machined cavity in bracket with inner cap. To regreasebearing, remove bracket (four nuts hold bracket to frame) and inner cap(two bolts). Clean old grease from bearing and cavity and repack withChevron SRI-2 or equivalent grease.

Commutator End BearingBearing has single shield and single seal with seal on side facingcommutator. To regrease bearing, snap out brushes and remove bracket(four nuts hold bracket to frame). Clean old grease from around bearing andcavity and repack around bearing and Chevron SRI-2 or equivalent grease.

Amount of grease to be added to motors is shown in Table H. See Table Jfor relubrication interval. Use Chevron SRI-2 or equivalent grease unlessmotor nameplate specifies special grease.

Recommended LubricantFor motors operating in ambient temperatures shown below, use thefollowing lubricants or their equivalent:

Ball Bearing Motors

Table H Coupled/Belted or Tandem Duty Grease Amounts

Using the table below, determine service condition on the basis of the mostsevere operating parameter (i.e. temperature, bearing load, atmosphere, oroperating hours per day).

Table I Service Condition

1 Motors must be specially designed for operation in ambient outside the range of –30 to 40 degrees C(–22 to 104 degrees F). Special grease is required.

2 “Extreme” service conditions are rare in actual practice. Corresponding lubrication cycles should therefore beapplied with caution. It is also advisable to check with Allen-Bradley for related special instructions.

Operating Temperature:–25 to 50 degrees C (–15 to 120 degrees F)

Chevron Oil – SRI No. 2Exxon – Unirex N2Shell Oil Co. – Dolium RTexaco, Inc. – Premium RB

Minimum Starting Temperature–60 degrees C (–76 degrees F)

Shell Oil Co. – Aeroshell 7

FrameVolume WeightCubic Inches Cubic Centimeters Ounces Grams

C180ATZ 1.0 16 0.5 14

ServiceCondition Ambient Temperature Bearing Load Atmosphere

OperatingHours/Day

Standard –18 to 40 degrees C(0 to 104 degrees F)

Steady Clean 8

Severe –30 to 50 degrees C(–22 to 122 degrees F)1

Medium Shock, Vibration(less than 0.2 in/sec.)

Medium Dirt,Abrasives, Corrosion

8 to 24

Extreme2 –54 to 65 degrees C(–65 to 149 degrees F)1

Heavy Shock, Vibration(more than 0.44 in/sec)

Heavy Dirt,Abrasives, Corrosion

8 to 24

DC Motors 17

Table J Relubrication Periods – Frames C180ATZ

1 Maximum speed occupying more than 30% of operating time.2 For Tandem drives increase frequency of lubrication by multiplying values by 0.8.

Lubrication – Frames C180ATZ

These motors are designed to route new grease directly into the bearing.The relubrication periods shown in Table J are offered as a guide for varyingservice conditions, speeds, bearing types and operating hours.

Important: Certain special motors may have a lubrication instruction platepermanently attached. These specific lubricating instructionmust be followed.

Lubrication Procedure

1. Relubrication with the shaft stationary and a warm motor isrecommended.

2. Locate the grease inlet at the top of the bearing hub, clean the area andreplace the 1/8 inch pipe plug with a grease fitting (if the motor is notequipped with a grease fitting).

3. When provided, remove grease drain plug located opposite the greaseinlet. The following motors do not have a grease drain plug, but have agrease relief around the grease inlet pipe:– Frames C180ATZ on commutator end (opposite drive end).– All C-Face and D-Flange frames on drive end.

4. Using a manual grease gun, pump in the recommended grease in theamount shown in Table H. This amount of grease will provide an amplesupply of lubricant between lubrication periods as determined fromTable J for the service condition listed in Table I. An excessive amountof grease will damage the motor.

Use Chevron SRI-2 grease or equivalent unless motor nameplatespecifies special grease. Use only clean, fresh grease from cleancontainers and handle carefully to keep it clean.

Maximum NormalOperating Speed (RPM)1 Frame

Relubrication Interval (Months)2

StandardService

SevereService

ExtremeService

3450 and higher C180ATZ 9 4 12400 - 3449 C180ATZ 24 9 31700 - 2399 C180ATZ 36 12 3800 - 1699 C180ATZ 36 24 8500 - 799 C180ATZ 48 36 12499 and lower C180ATZ 48 36 12

!ATTENTION: To guard against personal injury or death fromrotating parts or electrical shock, relubrication should only beperformed while the motor is stationary and disconnected fromthe power source.

18 DC Motors

In general, mixing of greases is not recommended. If an incompatiblegrease is used, the lube system must be repacked completely with thenew grease.

5. Wipe away any excess grease at the grease drain or relief and replacedrain plugs.

Repacking Bearings or Greasing New Bearings

When existing bearings have been completely cleaned of old grease orwhen bearings are replaced, use this procedure for packing the bearing.

1. Apply one bead of grease all around inboard side of bearing betweenbearing and inner cap, making sure that grease adheres to balls or rollers.

2. Apply one bead of grease all around outboard side of bearing, makingsure grease adheres to balls or rollers.

3. Completely fill grease inlet and outlet passage holes with grease.

4. Fill outboard bearing cavity 60% to 90% full of grease.

5. If possible, rotate shaft of assembled machine at least three revolutionsby hand to distribute grease within bearings before starting motor.

Bearings

These motors are designed to provide a mounting for anti-friction bearingsto give:

• Maximum protection to windings and interior of machine by preventinggrease leakage from bearing housing.

• Maximum protection to bearings against excess lubricant, insufficientlubricant, dirt and moisture.

Various types of anti-friction bearings are used in the wide range of framesas needed to meet specific load, speed and service requirements.

Most commonly used bearings are:

• Single row, open ball bearings for coupled and belted duty for framesC180ATZ. Frames DC180ATZ and DC210ATZ have a single-shieldedbearing on the commutator end.

Frequent bearing checks are recommended. If temperatures becomeexcessive, investigate immediately for the cause. Total bearing temperaturesshould not exceed 90 degrees C (194 degrees F). Causes for high bearingtemperature are:

• Contaminated grease.• Insufficient grease or excessive amount.• Incorrect grease.• Excessive load or thrust due to misalignment or motor overload.• Loose bearings.• Bearing failure.• Excessive ambient temperature.

DC Motors 19

Replacement bearings should be ordered from Allen-Bradley in order toobtain the same carefully selected bearing as the original. Bearings shouldnever be exposed by disassembly of the motor unless absolutely necessaryfor inspection or replacement of the bearing or maintenance in other parts ofthe machine. Protect good bearings from dirt and contamination at all times.Most bearing failures are caused by dirt.

The open ball bearings for motor frames C180ATZ are the same regardlessof whether application is coupled or belted.

BrushesBrush pressure is correctly established at the factory and maintained at thecorrect value throughout the life of the brush by means of a constantpressure design. Brushes and brush-holders should be clean so that thebrushes are free to move in the holders. Replace brushes with new brushesof the same grade before wear permits the rivet or tamped pigtail to scorethe commutator. It is best to change out complete set.

Fit the face of new brushes to the contour of the commutator with sandpaperonly, no emery abrasive. Keep brush lead (pigtail) connections tight.Replacement brushes should have sleeved pigtails.

CommutatorA commutator in good condition is clean and smooth with a medium polishand a light brown color. Keep clean by occasionally wiping with a canvaspad. Use no lubricant or emery abrasive. If a commutator becomes rough, itneeds to be resurfaced. Roughness can be easily detected with the machinerunning by resting a pencil-like rod of insulating material (dry wood) onone of the brushes. In mild cases, a commutator dressing stone can be used.Very rough or out of round commutators require turning in a lathe. In everycase, maintain concentricity and remove the minimum material required forproper cleanup. Undercut the mica approximately l/16” and polish. Adjustbrush holders for approximately 1/8” clearance to commutator.

The finished diameter and the minimum diameter of the commutator for thevarious frames sizes are as follows:

The commutator should be replaced if the final diameter would have to beturned down to a value less than minimum limits.

!ATTENTION: To guard against personal injury or death, ensurethat all power to the motor has been removed and the motor shaftis stationary. Brushes must not be touched or replaced whilemotor is energized or rotating.

FrameNew Diameter Minimum DiameterInches Millimeters Inches Millimeters

DC180ATZ &DC210ATZ

3.01 76.5 2.62 66.5

C180ATZ 4.12 104.8 3.66 93.0

20 DC Motors

Commutation

Intermittent sparking due to overloads or slight visible sparking does notnecessarily indicate poor commutation. Poor commutation exists whenthere is excessive sparking requiring abnormal maintenance. Every case ofexcessive sparking should be investigated to determine the cause andcorrect it. The chart in Table K may help in analyzing commutationproblems. DC motors and generators are brushed for full load current. Ifunit or units are consistently operated at less than 1/2” rated load acondition known as threading will result.

Table K Commutation Problem Quick Check

Symptom Identified By Possible Cause1. Excessive sparking at motor

or generator commutator.Sparking 1. Dirty or corroded commutator due to dirt,

ambient contaminants, oil or oil mist, etc.2. Brushes incorrectly seated.3. High or feather-edged mica.4. Faulty machine adjustment.5. Interpoles failed or improperly adjusted.6. Loss of brush spring tension.7. Brushes sticking in brush holder.8. Unit overload.9. Defective commutator or armature.10. Unequal spacing of holders around commutator.

2. High commutator barsproduce a rough commutator.

Generally associated with sparking and noisy operation ofthe brushes on the commutator.

1. Loose commutator.

3. Low commutator barsproduce rough commutator.

Generally associated with sparking and noisy operation ofthe brushes on the commutator.

1. Loose commutator.2. High mica.3. Open or high resistance connection at

commutator.4. Streaking or threading of

commutator surface.Rough commutator with associated sparking. Fine lines inbrush track.

1. Low average current density in brushes due tolight machine loading.

2. Contaminated atmosphere.3. Oil on commutator or oil mist in air.4. Humidity too low.5. Lack of film forming properties in brush.6. Brush too abrasive.

5. Bar etching or burning. Rough commutator with associated sparking and eventualflashover.

1. High mica.2. Operation of machine with brushes off neutral.3. Commutator dirty.4. Incorrect spring tension.5. Machine overload or rapid load change such as

plugging.6. Bar marking at pole-pitching

spacing.1. Two bars marking 180 degrees C (356 degrees F)

apart on 4-pole machine at start.2. Three bars marking 120 degrees C (248 degrees F)

apart on 6-pole machine at start.3. As pitch bar marking progresses, it will eventually

show at all bars on the machine.4. Associated sparking and eventual flashover.

1. Shorted commutator bars or coils.2. Open armature or field circuit.3. Unequal air gap.4. Cyclic disturbance either electrical or

mechanical.

7. Bar marking at slot-pitchspacing.

Sparking and marking of one or more bars at equalspacing around commutator according to bar-per-slot ratiowith eventual flashover.

1. Unequal compensation of armature coils. Theenergy unbalance is reflected into the last coil inthe slot to undergo commutation, and will resultin a spark at the brush.

8. Rapid commutator or brushwear.

Bright commutator surface. 1. Abrasive material under brush.2. Too abrasive a brush.3. Low average brush current density due to light

machine loading.4. Contaminated atmosphere.5. Humidity too low.6. Incorrect brush tension.

DC Motors 21

Windings

For long life, keep windings clean and dry. Dirt or dust can be removed bywiping them with a clean cloth, by blowing with clean, dry, low pressure airor by vacuum cleaner. Oil or grease can be removed with a cloth moistenedwith mineral solvent. Be sure not to get any solvent on the commutator andobserve all product warnings.

Filters – Cleaning

When supplied, filters on motors must be kept clean to assure proper airflow and cooling of the motor. The following procedure should be used toclean these filters:

1. For light accumulations of dust, use compressed air to clean.

2. For moderate accumulations, water may be used.

3. For heavy accumulations of dirt and grease, clean the filter using waterand detergent.

4. Always completely dry filter after cleaning with water.

5. After heavy cleaning, spray with a very light coat of protective oil toprotect against possible loss of plating.

Important: Do Not use flammable solvents to clean filters.

Important: Standard washable filters may not be suitable for motorsoperating in atmospheres with heavy concentrations of oil mist.Oil mist may be drawn into the motor and cause damage to thecommutator and windings. Contact Allen-Bradley for motorsoperating in heavy oil mist atmospheres.

Brakes

Motor mounted brake, when supplied, must be adjusted and maintained inaccordance with the instructions for the specific brake. Refer to separateinstructions supplied with the motor

Disassembly & ReassemblyInstructions

The motor design incorporates many new techniques which are described inthis section. It is recommended that these differences be understoodthoroughly before any disassembly work is done to avoid possible damageor harm to either machine and/or maintenance personnel.

22 DC Motors

Air Gap And Shimming

(Frame C180ATZ)

Main Pole

Steel or brass shims, when used, are placed between pole and frame. If forany reason the shims are removed they must be replaced under the samepoles. Main pole bolts are steel SAE Grade 5 (120,000 psi).

Axial Float

Frames C180ATZ have wavy spring washers between B.E. bracket andbearing. Axial float should be within the limits listed on the chart below.

Axial Float

Anti-friction Bearing Assemblies

The bearings are positioned and secured by various means depending onsize and application requirements. Open type ball bearings are used fordirect coupled and belt drive applications. Below are standard constructiondetails for the various frames.

DC180ATZ & DC210ATAZ

Drive end bearing fits in a machined cavity in the bracket with inner cap.Commutator end bearing has single seal on side facing commutator.

C180ATZ

Bearings fit in a machined cavity in the end brackets. Inner caps are used.

Bearing ReplacementRemove bearing by means of bearing puller. Clean bearing housing andbearing seat prior to assembly of bearing. Place new bearing in a bake ovenfor one hour at 121 degrees C (250 degrees F). Place bearing onto shaft andpush home to bearing shoulder. Hold it in place for a minimum of 30seconds.

After bearing has cooled down for about 1 minute, add 1/2 cu. in. of freshgrease into back of bearing. When the motor has been assembled, grease perinstructions found on page 15.

Frame Maximum MinimumAll 1.22 mm (0.048 in.) 0.20 mm (0.08 in.)

DC Motors 23

Brush Rigging and Brush Holders

The brush holders in all motors are often constant pressure design and donot require nor are capable of adjustment over the life of the brushes.

DC180ATZ & DC210ATZ

Conduit box is attached to the commutator end top hand hole cover andcannot be located on the side.

C180ATZ

Conduit box is located on the commutator end bracket.

Parts Identification C180AT, DC180ATZ & DC210ATZ

Number Description Number Description1 Grease Plug (C180 only) FE 12 Inner Coil2 Grease Plug (C180 only) BE 13 Armature Core3 Ball Bearing FE 14 Frame4 Ball Bearing BE 15 Armature Coil5 Rocker 16 Inner Fan6 Bracket FE 17 Key7 Bracket BE 18 Shaft8 Brush 19 Conduit Box9 Brush Holder 20 Bearing Cap BE10 Commutator 21 Bearing Cap (C180 only)

(Cap not shown)FE

11 Field Coil

Online DocumentationThe latest motor information can be obtained from the Allen-BradleyDrives & Motors home page on the World Wide Web at:http://www.controlmatched.com

Publication 1325L-UM001B-EN-P – August, 2001Supersedes 1325L-UM001A-EN-P dated May, 2001 Copyright © 2001 Rockwell Automation. All rights reserved. Printed in USA.